From 3671eb5c1b6853adf0b9c0ff393c04785c949397 Mon Sep 17 00:00:00 2001
From: Jonathan del Strother <me@delstrother.com>
Date: Thu, 19 Sep 2024 16:41:28 +0100
Subject: [PATCH 1/2] Fix output.to_stdout_from_any_process when $stdout has
 been reassigned

When running under rspec bisect runner, $stdout & $stderr are reassigned
to a StringIO, which would introduce spec errors.

("can't convert Tempfile into StringIO", when trying to reopen the
stream in CaptureStreamToTempfile)

Since CaptureStreamToTempfile reopens the stream rather than reassigning
it, I _think_ it makes sense to use STDOUT rather than whatever the
current value of $stdout is.
---
 lib/rspec/matchers/built_in/output.rb       |  4 ++--
 spec/rspec/matchers/built_in/output_spec.rb | 20 ++++++++++++++++++++
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/lib/rspec/matchers/built_in/output.rb b/lib/rspec/matchers/built_in/output.rb
index 888ccaee2..767915839 100644
--- a/lib/rspec/matchers/built_in/output.rb
+++ b/lib/rspec/matchers/built_in/output.rb
@@ -46,7 +46,7 @@ def to_stderr
         # Works when subprocesses print to stdout as well.
         # This is significantly (~30x) slower than `to_stdout`
         def to_stdout_from_any_process
-          @stream_capturer = CaptureStreamToTempfile.new("stdout", $stdout)
+          @stream_capturer = CaptureStreamToTempfile.new("stdout", STDOUT) # rubocop:disable Style/GlobalStdStream
           self
         end
 
@@ -55,7 +55,7 @@ def to_stdout_from_any_process
         # Works when subprocesses print to stderr as well.
         # This is significantly (~30x) slower than `to_stderr`
         def to_stderr_from_any_process
-          @stream_capturer = CaptureStreamToTempfile.new("stderr", $stderr)
+          @stream_capturer = CaptureStreamToTempfile.new("stderr", STDERR) # rubocop:disable Style/GlobalStdStream
           self
         end
 
diff --git a/spec/rspec/matchers/built_in/output_spec.rb b/spec/rspec/matchers/built_in/output_spec.rb
index 3873013d1..0440f867a 100644
--- a/spec/rspec/matchers/built_in/output_spec.rb
+++ b/spec/rspec/matchers/built_in/output_spec.rb
@@ -169,6 +169,16 @@ def print_to_stream(msg)
           end
         end
       }
+
+      it "passes even if $stderr has previously been set to a StringIO" do
+        original_stderr = $stderr
+        begin
+          $stderr = StringIO.new
+          expect { print_to_stream("foo") }.to output("foo").to_stderr_from_any_process
+        ensure
+          $stderr = original_stderr
+        end
+      end
     end
 
     RSpec.describe "output.to_stdout_from_any_process matcher" do
@@ -181,6 +191,16 @@ def print_to_stream(msg)
           end
         end
       }
+
+      it "passes even if $stdout has previously been set to a StringIO" do
+        original_stdout = $stdout
+        begin
+          $stdout = StringIO.new
+          expect { print_to_stream("foo") }.to output("foo").to_stdout_from_any_process
+        ensure
+          $stdout = original_stdout
+        end
+      end
     end
 
     RSpec.describe "output (without `to_stdout` or `to_stderr`)" do

From 392050b46ac00703d46e0bbadd8519785cfab29d Mon Sep 17 00:00:00 2001
From: Jonathan del Strother <me@delstrother.com>
Date: Fri, 20 Sep 2024 16:24:49 +0100
Subject: [PATCH 2/2] Reassign $stdout/$stderr in CaptureStreamToTempfile

Otherwise it doesn't work when $stderr has previously been reassigned,
like in the rspec-core test suite
---
 lib/rspec/matchers/built_in/output.rb | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/lib/rspec/matchers/built_in/output.rb b/lib/rspec/matchers/built_in/output.rb
index 767915839..97c00c9e5 100644
--- a/lib/rspec/matchers/built_in/output.rb
+++ b/lib/rspec/matchers/built_in/output.rb
@@ -46,7 +46,7 @@ def to_stderr
         # Works when subprocesses print to stdout as well.
         # This is significantly (~30x) slower than `to_stdout`
         def to_stdout_from_any_process
-          @stream_capturer = CaptureStreamToTempfile.new("stdout", STDOUT) # rubocop:disable Style/GlobalStdStream
+          @stream_capturer = CaptureStreamToTempfile.new("stdout")
           self
         end
 
@@ -55,7 +55,7 @@ def to_stdout_from_any_process
         # Works when subprocesses print to stderr as well.
         # This is significantly (~30x) slower than `to_stderr`
         def to_stderr_from_any_process
-          @stream_capturer = CaptureStreamToTempfile.new("stderr", STDERR) # rubocop:disable Style/GlobalStdStream
+          @stream_capturer = CaptureStreamToTempfile.new("stderr")
           self
         end
 
@@ -213,7 +213,7 @@ def capture(block)
       end
 
       # @private
-      class CaptureStreamToTempfile < Struct.new(:name, :stream)
+      class CaptureStreamToTempfile < Struct.new(:name)
         def capture(block)
           # We delay loading tempfile until it is actually needed because
           # we want to minimize stdlibs loaded so that users who use a
@@ -223,19 +223,29 @@ def capture(block)
           # thread, fileutils, etc), so it's worth delaying it until this point.
           require 'tempfile'
 
-          original_stream = stream.clone
+          stream = name == 'stdout' ? STDOUT : STDERR # rubocop:ignore Style/GlobalStdStream
           captured_stream = Tempfile.new(name)
 
           begin
+            if name == 'stdout'
+              $stdout = captured_stream
+            else
+              $stderr = captured_stream
+            end
             captured_stream.sync = true
             stream.reopen(captured_stream)
             block.call
             captured_stream.rewind
             captured_stream.read
           ensure
-            stream.reopen(original_stream)
+            stream.reopen(stream)
             captured_stream.close
             captured_stream.unlink
+            if name == 'stdout'
+              $stdout = stream
+            else
+              $stderr = stream
+            end
           end
         end
       end